i have workbook a to m, and x

i wrote a macro using vb to...
open workbook a,
then copy information from workbook a to workbook x,
close workbook a,
then repeat the procedure for all workbooks.

but due to the amount of data that every workbooks has,
the windows dialog box will said something like 'do you
want to empty the clipboard' when it's trying to close the
workbook.

how to i automate this so it will empty the clipboard
before it closes the file.

thx.